For many pathologies and diseases, diagnostic images are used for screening, initial diagnosis and treatment follow up. As a result, radiological findings typically are followed over time. Examples of such radiological findings are a liver tumor lesion, a lung nodule, a vessel stenosis, a fatty liver, some infection, an infarct etc. Radiologists rely not only on the latest available images but on the whole history in their decision making. The history might include the time when to intervene, when to change a treatment or when to determine the next follow up interval.
Image examination is often based on a series of medical images acquired by medical image acquisition modalities, such as x-ray device, ultrasound devices, CT or MR scanners. Especially three dimensional image acquisition technologies, such as CT or MR, result in a large number of images. Since medical imaging acquisition often result in hundreds of images, it becomes very time consuming to navigate through the images to identify the image or the small number of images relevant for the medical finding in prior image scans to be able to determine the change of the findings over time. The change of the findings can for example indicate, whether a tumor is growing or a stenos worsening. Accessing historical radiological findings of a patient becomes challenging especially when patients move from one healthcare provider to another.
Medical software applications for accessing findings are known, which document and manage individual radiological findings, for example in a list. It is possible to create and include a new finding into an existing examination file including prior findings. This can be done manually or suggested by the medical software application based on an algorithm. In such a case the new finding can be linked to the closed existing findings based on the three dimensional image volumes which were the basis for the previous and the new finding, respectively.
Different methods of three dimensional registration of image volumes are known. However, these methods require the two image volumes to be registered to be available locally. Since the linking of the new with the previous finding takes place at the time the radiologist reads the new finding, the three dimensional image volume is required to be available locally at this time as well to perform the image registration.